It is known that halogen-containing compounds are frequently utilized with polymers, the flame retardant property being imparted by the halogen present therein. A large number of different compositions are known for rendering polymers inflammable or self-extinguishing, such compositions being based generally on the use of various halogenated compounds. It is also known that certain bromine compositions are more effective flame retardant agents than the corresponding chlorine compounds.
According to U.S. Pat. No. 3,864,306, there are disclosed blends of polymers with flame retardant agents consisting of esters of brominated dipentaerythritol. These fire retardant agents have a relative low bromine content, in the range of between 37% for the dibenzoate and 53% for the diacetate esters of tetrabromodipentaerythritol. The latter one, has the additional disadvantage of being a viscous liquid which requires special handling in preparing the adequate formulations. As known, compounders of thermoplastics like polyolefins, styrenes etc. prefer handling free flowing powders as additives rather than liquid.
The incorporation of flame retardant can effect in some polymers the light stability particularly where out-door exposure is of concern. It is known that brominated aliphatic neopentylic structures, encounter superior Ultra Violet stability.
Another important property required for flame retardant polymer compositions is the thermal stability. An efficient flame retardant agent should also possess good thermal stability.